The community member is looking to disallow some old IPs from their previous site, but they cannot find the file. In the comments, another community member suggests that there is no robots.txt file, and that the community member may need to host elsewhere and point to it. Another community member provides a link to a related discussion, but there is no explicitly marked answer.
There's no robots.txt. There are a few threads here discussing that. I think you'll need to host elsewhere and point to it. I haven't done it yet myself.